The manufacture of biopharmaceuticals, particularly drugs based on bioactive molecules such as proteins, peptides and nucleic acids, requires the production and purification of these molecules on an industrial scale. In particular, the increasing demand for monoclonal antibodies (MAbs) as biopharmaceutical products has promoted the development of cell cultures with high expression levels and, as a consequence, the demand for more efficient purification processes has increased. For example, monoclonal antibodies are revolutionising the treatment of many illnesses and they have become one of the main indicators of the direction drug treatments are moving. The latest estimates of the European monoclonal antibody therapeutics market arrive at a figure of $11.4 billion (8.7 billion) by 2011. This increased demand has necessitated the use of large, advanced chromatography systems comprising columns packed with separations media such as SEPHAROSE™, MABSELECT™, SOURCE™ and CAPTO™ (GE Healthcare).
During chromatographic separation of biopharmaceuticals, it is of critical importance to ensure that the process is conducted under sterile conditions and that potentially harmful contaminants are removed from the system before use. Contamination with bacteria and other microbes is an often encountered problem within many biotechnological and biomedical applications. Various agents are known for their ability to inactivate and/or destroy microbial populations, for example, sodium hydroxide, peracetic acid, phosphoric acid, ethylene oxide, chlorine dioxide and benzyl alcohol. However, disinfection of columns and chromatographic media is cumbersome, particularly disinfection of proteinaceous media, i.e. chromatographic media provided with proteinaceous ligands, such as various affinity chromatography media. The most effective disinfectants and sanitation reagents such as strong acids or alkalis, quaternary ammonium compounds, halogen-containing compounds, oxidizing agents, and phenols and related compounds are considered harmful to most chromatography media particularly to proteinaceous affinity media. In addition, sterilization methods, such as gamma irradiation and autoclaving, are also considered to have large deleterious effects on those media.
Furthermore, many sanitation or sterilization methods involving acids or alkalis, quaternary ammonium compounds, halogen-containing compounds, oxidizing agents, and phenols and related compounds are harmful and/or toxic. Thus, methods are required for the efficient sterilization of sensitive material, such as chromatographic media.
U.S. Pat. No. 5,817,528 (Böhm, W. et al) describes a method for producing a sterile and pyrogen-free column containing a matrix material to which a protein is coupled. Suitably, the protein coupled to the column is Staphylococcus aureus Protein A, or Streptococcus Protein G, or the protein may be an antibody such as anti-human LDL immunoglobulin or anti-human Ig immunoglobulin. The method provides a column matrix material such as an agarose which is chemically activated, using CNBr/triethylamine or using 1,1′-carbonyldiimidazole. The chromatography matrix material is preferably sterilized by steam sterilization at 115° C., before combining with pathogen-free, purified protein under aseptic conditions so as to couple the protein to the matrix material.